I recently picked up an Air Force 22lr conversion kit and a handful of 10 round magazines from another member here on the forum. In doing reaserch on this conversion kit I've found the general consensus to be the following:
1. Although similiar to the Army m261 kits/CMMG kits, the AF version is " more reliable" and there is little to no compatability including magazines.
2. This was the only last round hold open kit for some time.
3. While the kit itself is not terribly pick about ammo, the twist rate of your barrel should play a major role in ammo selection.
So how did it shoot?
Testing was done with a Windham Weaponry 20" goverment rifle (an m16A4 clone with a 1/7 twist). This rifle was zeroed using the USMC procedure for something like 36 yards about a year ago with IMI 62gr 5.56.
My first group was made shooting center mass on 12"x18" silhouette using Winchester 62gr 5.56 at 50 yards. After changing the bolt and mag, a second group was made using CCI mini mags also aimed center mass on an identical target. This group spread significantly and the point of impact also shifted pretty low.
The rest of the cci mini mags were used at 25 yards shooting reactive targets and although I did have to hold slightly high I would say it's definitely workable at that distance. Using a hi-vis silhouette, I also mag dumped about 25 rounds as fast as I could and with no hold (see results below). Mag changes are quick and familiar given the full size and weight of the Teflon 10 round magazines. The bolt hold open feature worked about half the time and I found more than once that I had to charge the rifle after inserting a fresh mag on a closed bolt. The short stroke of the 22lr BCG will also catch you off guard if you're not used to it.
Please note that I had 1 malfunction during this time but didn't think to take a picture before clearing. This was almost certainly caused by a single round of 22lr I found on the bench from a diffrent range trip that I threw in with the last of the CCIs on my last mag. The nose of this lead round was damaged and caused a feeding issue with the round above it.
At this point I switched back to the standard BCG and magazine. I fired another group of Win m855 at the head of the first silhouette. This group was high right but probably had more to do with me than the rifle. After seeing this group I rang the steel plates at 100 and 200 yards a few times to collect myself before switching to the 22lr kit for the last time.
The last group of the day was shot with CCI stingers at the head of the second 50 yard silhouette. This group moved considerably to the left and one round was off the paper. Instead of wasting the rest of the CCI stingers rounds I switched to 5.56 and kept shooting steel between 100 and 300 yards.
Key take aways:
1. It's going to take a lot of testing to find a good 22lr round that shoots point of aim, point of impact.
2.The conversion kit is accurate enough within 50 yards to be a decent training aid
3. Soaking the kit in CLP might help the last round hold open feature?
4. 22lr was not made to shot from a 1/7 twist barrel but it's still fun and is accurate enough to be "practical"
1. Although similiar to the Army m261 kits/CMMG kits, the AF version is " more reliable" and there is little to no compatability including magazines.
2. This was the only last round hold open kit for some time.
3. While the kit itself is not terribly pick about ammo, the twist rate of your barrel should play a major role in ammo selection.
So how did it shoot?
Testing was done with a Windham Weaponry 20" goverment rifle (an m16A4 clone with a 1/7 twist). This rifle was zeroed using the USMC procedure for something like 36 yards about a year ago with IMI 62gr 5.56.
My first group was made shooting center mass on 12"x18" silhouette using Winchester 62gr 5.56 at 50 yards. After changing the bolt and mag, a second group was made using CCI mini mags also aimed center mass on an identical target. This group spread significantly and the point of impact also shifted pretty low.
The rest of the cci mini mags were used at 25 yards shooting reactive targets and although I did have to hold slightly high I would say it's definitely workable at that distance. Using a hi-vis silhouette, I also mag dumped about 25 rounds as fast as I could and with no hold (see results below). Mag changes are quick and familiar given the full size and weight of the Teflon 10 round magazines. The bolt hold open feature worked about half the time and I found more than once that I had to charge the rifle after inserting a fresh mag on a closed bolt. The short stroke of the 22lr BCG will also catch you off guard if you're not used to it.
Please note that I had 1 malfunction during this time but didn't think to take a picture before clearing. This was almost certainly caused by a single round of 22lr I found on the bench from a diffrent range trip that I threw in with the last of the CCIs on my last mag. The nose of this lead round was damaged and caused a feeding issue with the round above it.
At this point I switched back to the standard BCG and magazine. I fired another group of Win m855 at the head of the first silhouette. This group was high right but probably had more to do with me than the rifle. After seeing this group I rang the steel plates at 100 and 200 yards a few times to collect myself before switching to the 22lr kit for the last time.
The last group of the day was shot with CCI stingers at the head of the second 50 yard silhouette. This group moved considerably to the left and one round was off the paper. Instead of wasting the rest of the CCI stingers rounds I switched to 5.56 and kept shooting steel between 100 and 300 yards.
Key take aways:
1. It's going to take a lot of testing to find a good 22lr round that shoots point of aim, point of impact.
2.The conversion kit is accurate enough within 50 yards to be a decent training aid
3. Soaking the kit in CLP might help the last round hold open feature?
4. 22lr was not made to shot from a 1/7 twist barrel but it's still fun and is accurate enough to be "practical"
Last edited: